The present invention relates to image forming apparatus and in particular to electrostatographic printing apparatus and more particularly to a processing cartridge which is removably mountable into the main body of such apparatus. More specifically, the present invention provides a new processing cartridge with a one time function discard sheet which provides a one time function to either the processing cartridge or the main body of the image forming apparatus when a new cartridge is inserted in the main body of the apparatus and the sheet is withdrawn.
In electrostatographic reproducing apparatus commonly used today a photoconductive insulating member is typically charged to a uniform potential and thereafter exposed to a light image of an original document to be reproduced. The exposure discharges the photoconductive insulating surface in exposed or background areas and creates an electrostatic latent image on the member which corresponds to the image contained within the original document. Alternatively, a light beam may be modulated and used to selectively discharge portions of the charged photoconductive surface to record the desired information thereon. Typically, such A system employs a laser beam. Subsequently, the electrostatic latent image on the photoconductive insulating surface is made visible by developing the image with developer powder referred to in the art as toner. Most development systems employ developer which comprises both charged carrier particles and charged toner particles which triboelectrically adhere to the carrier particles. During development the toner particles are attracted from the carrier particles by the charged pattern of the image areas of the photoconductive insulating area to form a powder image on the photoconductive area. This toner image may be subsequently transferred to a support surface such as copy paper to which it may be permanently affixed by heating or by the application of pressure.
In order to minimize maintenance costs by permitting the operator to replace worn out or exhausted processing units in electrostatographic apparatus, it has been suggested to incorporate one or more of the processing means of the apparatus in a disposable or removable cartridge. In this way, the operator can readily remove the cartridge when its operational life has been exhausted and insert a new cartridge. Many commercial applications employ this modular concept for the various processing stations. For example, the imaging member, developer assembly and cleaner assembly may be combined in a single unit or cartridge which has a limited life at the end of which it may be discarded and replaced with a new cartridge or unit. Alternatively, a charging device may be added to the unit or the unit may contain either of the developer or the cleaner. When replacing a used cartridge with a new cartridge, it may be necessary to perform one or more one time functions to enable the new cartridge to perform satisfactorily, to initiate functionality of processing elements, to rejuvenate a functional part of the main body of the apparatus or to provide an initial supply of some material to either the new cartridge or the main body of the apparatus. For example, in a new processing cartridge containing a cleaning system which includes a blade cleaner, it may be necessary to initially lubricate the cleaning nip formed between the blade tip and the imaging member. Alternatively, it may be desirable merely to initiate the functional relationship between the blade and the imaging member. If the nip is not adequately lubricated, there will be a relatively high coefficient of friction between the blade tip and imaging surface to such an extent that the edge or tip of the blade will tend to tuck under as the photoreceptor is moved relative thereto thereby causing a cleaning failure which may only be capable of being remedied by replacement of the cartridge with a new cartridge. In addition, in such apparatus wherein a roll fuser is used and contained within the main body of the apparatus, it may be desirable to provide an initial image of a release agent such as silicone oil to the fuser roll on insertion of a new processing cartridge.